changed recipe class

lib/models/recipe.dart

@@ -15,6 +15,7 @@ class Recipe {
     this.ingredients = const [],
     this.keywords = const [],
     this.steps = const [],
+    this.servingSize = 0,
   });
 
   final Duration cookTime;
@@ -29,6 +30,7 @@ class Recipe {
   final Duration prepTime;
   final List<String> steps;
   final String title;
+  final int servingSize;
 
   Duration get totalTime => cookTime + prepTime;
 
@@ -46,6 +48,7 @@ class Recipe {
     List<String>? keywords,
     MealCategory? mealCategory,
     Cuisine? cuisine,
+    int? servingSize,
   }) {
     return Recipe(
       id: id ?? this.id,
@@ -66,6 +69,7 @@ class Recipe {
           : List<String>.from(this.keywords),
       mealCategory: mealCategory ?? this.mealCategory,
       cuisine: cuisine ?? this.cuisine,
+      servingSize: servingSize ?? this.servingSize,
     );
   }
 }

lib/services/providers/recipe_provider.dart

@@ -23,6 +23,13 @@ class RecipeProvider extends ChangeNotifier {
     }
   }
 
+  void updateServingSize(int servingSize, {bool silent = false}) {
+    _recipe = _recipe.copyWith(servingSize: servingSize);
+    if (!silent) {
+      notifyListeners();
+    }
+  }
+
   void updateDifficulty(Difficulty difficulty, {bool silent = false}) {
     _recipe = _recipe.copyWith(difficulty: difficulty);
     if (!silent) {
@@ -73,14 +80,14 @@ class RecipeProvider extends ChangeNotifier {
     }
   }
 
-  void updateMealCategory(MealCategory mealCategory, {bool silent = false}) {
+  void updateMealCategory(MealCategory? mealCategory, {bool silent = false}) {
     _recipe = _recipe.copyWith(mealCategory: mealCategory);
     if (!silent) {
       notifyListeners();
     }
   }
 
-  void updateCuisine(Cuisine cuisine, {bool silent = false}) {
+  void updateCuisine(Cuisine? cuisine, {bool silent = false}) {
     _recipe = _recipe.copyWith(cuisine: cuisine);
     if (!silent) {
       notifyListeners();